NASA declares Mars Spirit rover 'healed'

Saturday, February 7, 2004

PASADENA, Calif. -- NASA on Friday pronounced its Spirit rover cured of the computer ills that crippled the vehicle for two weeks and had threatened its mission to search for geologic evidence that Mars was once a wetter planet. "I think I can say this morning with as much certainty as we can say anything here that our patient is healed," mission manager Jennifer Trosper said. The rover, which abruptly stopped sending scientific data to Earth last month, underwent delicate repairs as programmers deleted files and cleaned out its flash memory.

It was able to resume scientific work Thursday.

The six-wheeled vehicle "did exactly what we wanted it to do, and it performed perfectly, and it's in great health right now," Trosper said.

The problem caused computer files to accumulate, consuming the spacecraft's memory, "and eventually we ran out," said Glenn Reeves, who designed the probe's software.

Spirit and its twin, Opportunity, on the other side of Mars, are now being monitored to prevent accumulation of files in their flash memories, similar to the memory used by digital cameras to store pictures.

NASA quickly put Spirit back to work, commanding it to lightly dust off the surface of a volcanic rock and photograph the freshly exposed surface with its microscopic imager.

The five-minute task swept off a surprising amount of dust to reveal a circular patch of dark, unblemished basalt, said scientist Stephen Gorevan, of Honeybee Robotics, which built the roughly $4 million pair of drills used for the task.

NASA planned for Spirit to drill into the rock before embarking on an 800-foot drive toward a crater. The trip should begin Saturday at the earliest, and could take a month to complete.

Meanwhile, Opportunity on Friday drove about five feet closer to a rocky outcrop that scientists want to study in detail. The rover ended up about 18 inches short of its target, a gap engineers blamed on wheel slippage in the dry martian sand.

NASA planned for Opportunity to scoot up to the outcrop Saturday and then begin studying fine-scaled layering in the bedrock. Scientists believe the layers could have been laid down in water.

Opportunity probably will spend several more weeks inside the 72-foot diameter crater in which it landed, studying the outcrop and then turning to the rusty soil beneath its six wheels. Portions of the soil appear rich in hematite, an iron-bearing mineral that typically forms in liquid water.

On Friday, NASA showed several black-and-white pictures taken by Opportunity as it scuttled across the crater. The photographs recorded the rover's progress as it moved away from its lander and toward the outcrop.

"These are some frameable shots," mission manager Matt Wallace said.

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